摘要
运用沉积学和岩相古地理学原理,通过对尖山组岩石的颜色、结构、原生沉积构造等岩性特征及其空间配置的研究,以及有关地质图件的综合分析,从尖山组中识别出滨岸相和浅海相2种沉积相,滨岸相又可细分为无障壁砂质海岸沉积亚相和障壁岛-潟湖沉积亚相。中元古界长城系尖山组二段二亚段的半局限海湾障壁岛-潟湖亚相是研究区锰矿的主要形成环境,控制着锰矿的形成与分布。成矿时海水深度较浅,且沉积环境较稳定,有利于氧化锰矿的富集,沉积了一套以软锰矿、硬锰矿、褐铁矿矿石为主的层状或似层状的氧化锰矿床。成矿后,在动力和热力的作用下,发生区域变质作用,使矿床中的赤铁矿变为磁铁矿,矿物成分重新排列,具有明显的条带状构造,矿层顶、底板围岩为粉砂质板岩,成因类型为海相沉积变质型锰矿床。
Based on the principles of sedimentology, coal geology and paleogeography, the paper studied the lithologie characteristics of rocks in Jianshan formation, including color, structure and primary sedimentary structures. Combined with spatial configuration research and geological maps, the group identified two sendimentary facies from Jianshan formation, namely littoral facies and neritic facies, where littoral facies can be subdivided into sediment subfacies of sandy coast without barrier and the barrier island - lagoon sediment subfaeies. The barrier island - lagoon subfacies of semi-restricted bay formed in 2nd layer of 2nd section in Jianshan formation, mesoproterozoic erathem Changcheng system is the main environment of manganese mineralization in the studied area, controlling the formation and dis- tribution of manganese. During the process of mineralizing, the sea was shallow and the sedimentary en- vironment was stable, which was advantageous to the enrichment of manganese oxide ore. Consequently, a set of layered or stratiform-like oxidized manganese deposits was formed, with major ores being pyrolusite, psilomelane and limonite. After metallogenesis, regional metamorphism took place under the effect of the dynamic force and heat, transferring the hematite into magnetite. The mineral composition is thus rearranged with obvious banded structure. The surrounding rock of seam roof and floor is silty slate, and the genetic type is marine sedimentary-metamorphose Mn deposit.
出处
《西北地质》
CAS
CSCD
2013年第3期116-121,共6页
Northwestern Geology
基金
内蒙古自治区多金属矿普查基金项目(09-1-KC141)
关键词
尖山组
含锰地层
沉积相
成矿条件
成因类型
Jianshan formation
manganese-bearing strata
sedimentary facies~ metallogenic con-ditions~ genetic type
